抄録
The membrane materials are generally in various states of biaxial deformation in membrane structures, and also have visco-elasticity in addition to the peculiar nonlinearity. The biaxial extension curves, therefore, should be measured under the experimental conditions of iterative extension and various tensile speeds. In this paper, the authors selected PTFE coated plain-weave glass fiber and PVC coated plain-weave polyester fiber fabrics as the specimens, and measured the uni/biaxial extension curves up to the design stress (assumed to be 20% of the uniaxial breaking stress) under the experimental conditions of iterative extension and two different tensile speeds. The nonlinearity, the slope, and the iteration time up to convergence of the extension curves were studied. The dependences of these factors on tensile speed were also discussed. The main result of discussions was that the slope of extension curves depended upon tensile speed.
